1. Field of the Invention
The disclosure relates in general to a semiconductor device and methods of manufacturing the same, and more particularly to an ultra-high voltage n-type-metal-oxide-semiconductor (UHV NMOS) device with improved performance and methods of manufacturing the same.
2. Description of the Related Art
There is currently an ongoing drive toward the downscaling of device dimensions in virtually all aspects of electronic device manufacture. Smaller electronic devices tend to be more popular than larger, more bulky devices when both devices have substantially equivalent capabilities. Accordingly, being able to fabricate smaller components would clearly tend to facilitate the production of smaller devices that incorporate those components. However, many modern electronic devices require electronic circuitry to perform both actuation functions (e.g., switching devices) and data processing or other decision making functions. The use of low-voltage complementary metal-oxide-semiconductor (CMOS) technologies for these dual functions may not be practical. Thus, high-voltage integrated circuits (HVIC) or power-integrated circuits (PIC) have been developed to attempt to integrate high-voltage device structures with low voltage device structures on a single chip. There are two major challenges in HVIC: (1) to achieve a high breakdown voltage for ultra-high voltage (UHV) device; and (2) to effectively isolate between the UHV device and adjacent CMOS circuit.
Some examples of devices that involve switching at relatively high-voltage levels include drivers for flat panel displays, lighting and ballast applications (e.g., light emitting diode (LED) lighting), power supplies (e.g., mobile device chargers), and numerous other products. The high-voltage MOS devices that are desirable for employment in these applications should desirably possess a high breakdown voltage, such as to prevent punch through from a high-voltage area to a low-voltage area. Also, the semiconductor devices, for example, the N-type metal-oxide-semiconductor device suitable for ultra-high-voltage (UHV) operation, generally require good performance during operation, and could be manufactured by a low-cost and easy-to-carry-out manufacturing process.